Method of producing silicon single crystal

Abstract

A method of producing a silicon single crystal, in which a cylindrical partition is immersed in a molten pure silicon liquid or molten silicon liquid containing a Sb dopant within a crucible and the molten liquid inside the partition is pulled up from the crucible to produce the silicon single crystal, wherein an interval between a lower end of the partition and a crucible bottom is changed to control an oxygen concentration in the pulling-up silicon single crystal. The interval is reduced in the case where the oxygen concentration in the pulling-up silicon single crystal is to be increased while the interval is increased in the case where the oxygen concentration is to be reduced.

What is claimed is: 
     
       1. A method of producing a silicon single crystal, comprising the steps of: pulling up a silicon single crystal from a molten silicon liquid in a crucible, the silicon single crystal being pulled up at a position located inside a cylindrical partition immersed in the molten silicon liquid, the partition being immovably fixed relative to the crucible so as to provide a set interval through which molten silicon flows from outside to inside the partition, the interval extending between a lower end of said partition and a bottom of said crucible; and   adjusting the interval at a set distance prior to the pulling-up step so as to control an oxygen concentration in the silicon single crystal pulled-up from the melt.   
     
     
       2. A method of producing a silicon single crystal as set forth in claim 1, wherein said interval is reduced in the adjusting step so that the oxygen concentration in the silicon single crystal pulled-up from the melt is increased. 
     
     
       3. A method of producing a silicon single crystal as set forth in claim 1, wherein said partition is a heat-resisting member made of quartz or ceramics. 
     
     
       4. A method of producing a silicon single crystal as set forth in claim 1, wherein said crucible is composed of an inner crucible made of quartz and an outer crucible made of graphite. 
     
     
       5. A method of producing a silicon single crystal as set forth in claim 4, wherein an outside diameter of said partition is 60 to 90% of an outside diameter of said inner crucible. 
     
     
       6. A method of producing a silicon single crystal as set forth in claim 5, wherein the outside diameter of said partition is about 75% of the outside diameter of said inner crucible. 
     
     
       7. A method of producing a silicon single crystal as set forth in claim 1, wherein a thickness of said partition is 5 to 20 mm. 
     
     
       8. A method of producing a silicon single crystal as set forth in claim 7, wherein the thickness of said partition is 7 to 8 mm. 
     
     
       9. A method of producing a silicon single crystal as set forth in claim 1, wherein said interval is increased in the adjusting step so that the oxygen concentration in the silicon single crystal pulled-up from the melt is decreased. 
     
     
       10. A method of producing a silicon single crystal, comprising the steps of: pulling up a silicon single crystal from a molten silicon liquid containing antimony as a dopant in a crucible, the silicon single crystal being pulled up at a position located inside a cylindrical partition immersed in the molten silicon liquid, the partition having a thickness of 5 to 20 mm and being immovably fixed relative to the crucible so as to provide a set interval through which molten silicon flows from outside to inside the partition, the interval extending between a lower end of said partition and a bottom of said crucible;   adjusting the interval at a set distance prior to the pulling-up step so as to control an oxygen concentration in the silicon single crystal pulled up from the melt; and   controlling a rate of evaporation of Sb 2  O 3  by adjusting the temperature of the molten liquid inside the partition, whereby the silicon single crystal has an oxygen concentration of greater than 15×10 17  atoms/cm 3 .   
     
     
       11. A method of producing a silicon single crystal as set forth in claim 10, wherein said interval is reduced in the adjusting step so that the oxygen concentration in the silicon single crystal pulled up from the melt is increased. 
     
     
       12. A method of producing a silicon single crystal as set forth in claim 10, wherein said partition is a heat-resisting member made of quartz or ceramics. 
     
     
       13. A method of producing a silicon single crystal as set forth in claim 10, wherein said crucible is composed of an inner crucible made of quartz and an outer crucible made of graphite. 
     
     
       14. A method of producing a silicon single crystal as set forth in claim 13, wherein an outside diameter of said partition is 60 to 90% of an outside diameter of said inner crucible. 
     
     
       15. A method of producing a silicon single crystal as set forth in claim 14, wherein the outside diameter of said partition is about 75% of the outside diameter of said inner crucible. 
     
     
       16. A method of producing a silicon single crystal as set forth in claim 10, wherein a thickness of said partition is 5 to 20 mm. 
     
     
       17. A method of producing a silicon single crystal as set forth in claim 16, wherein the thickness of said partition is 7 to 8 mm. 
     
     
       18. A method of producing a silicon single crystal as set forth in claim 10, wherein said interval is increased in the adjusting step so that the oxygen concentration in the silicon single crystal pulled-up from the melt is decreased.